薄互层砂岩油藏开发前期采收率预测方法研究

Study on recovery prediction methods of thin interbed sandbone reservoir

南海西部乌石油田A井区为典型的薄互层砂岩油藏,单砂体厚度1.0 m左右,砂体展布及连通性认识不清,开发前期采收率预测难度大,影响油田建产。开发实践表明,砂体连通性与合理注采井距是影响薄互层砂岩油藏注水开发采收率的关键因素,针对采收率预测,经验公式法无法考虑砂体连通性,地质综合法虽考虑了注采系统,但各参数的定量取值以经验为主。通过类比已开发油田井网部署,依托沉积相定量地质知识库确定合理注采井距,并结合概念模型及均质模型开展采收率预测,为薄互层砂岩油藏开发前期采收率预测研究提供了借鉴。

Block A of Wushi oilfield in the South China Sea is a typical thin interbed sandbone reservoir with the thickness of single sand body of about 1.0 m.The distribution and connevtivity of sand body are not clear,and it is difficult to predict the recovery in the early stage of oilfield development,which affects the construction and production of Wushi oilfield.The development practice showed that sand body connectivity and reasonable injection-production well space were the key factor affecting the recovery of thin interbed sandstone reservoir.For recovery prediction,the empirical formula method cannot take sand body connectivity into account,while the geological syntheis method is dominated by experience although injection-production system is considered.By simulating well pattern of developed oilfields,reasonable injection-production well space is determined based on quantitative geological knowledge base of sedimentary facies,recovery prediction is carried out combining with reservoir numerical simulation,which provides a reference for early prediction of thin interbed sandbone reservoir.